<p>From Barron's 7th edition (newest) diagnostic test #27:</p>

<p>How many different ways can the letters of MINIMUM be arranged if all 7 letters are used each time?</p>

<p>a.7

b.42

c.420

d.840

e.5040</p>

<p>The answer is c. I already understand permutations and combinations. For this problem I did "7 Pr 7" and got 5040 as my answer. This is obviously wrong since there are "repeats". You must get rid of repeats by dividing out the repeats. So you divide by "3 Pr 3" and "2 Pr 2" to account for the 3 M's and 2 I's respectively. Is this correct?</p>